Broken valve and 3 cylinder '95 K1100LT

I added too much additive to my '95 K1000LT and it ended up killing a valve and killing a cylinder. My mechanic killed the fuel injector to the dead cylinder and the bike runs a little rough but it runs in 3.

How long will the bike limp along like this? Another year? The Summer? Next month? Next week? Can I ride from DC to the Hudson Valley and back this summer? I really love the bike.

My mechanic told be the bike requires either a new engine or a laborious repair (he has a spare K1100 motor) and just wants me to get a replacement used bike (looking at an '83 R80RT).

What would you do? Any experience, any advice?

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chrisabraham said:

I added too much additive to my '95 K1000LT and it ended up killing a valve and killing a cylinder. My mechanic killed the fuel injector to the dead cylinder and the bike runs a little rough but it runs in 3.

How long will the bike limp along like this? Another year? The Summer? Next month? Next week? Can I ride from DC to the Hudson Valley and back this summer? I really love the bike.

My mechanic told be the bike requires either a new engine or a laborious repair (he has a spare K1100 motor) and just wants me to get a replacement used bike (looking at an '83 R80RT).

What would you do? Any experience, any advice?

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Click to expand...

What additive? How much is too much?

PGlaves said:

What additive? How much is too much?

Click to expand...

Probably closer to half a bottle of Seafoam in a 5.1 gallon K1100LT tank if I'm honest with you. I'm told the additive superheats the engine when it's running through. Please forgive me, KBiking Gods. That's why I can't have nice things.

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Chris,

From Seafoam website:


"How much Sea Foam should I add to my fuel?


For routine fuel system (gas tank to engine) maintenance, one can of Sea Foam Motor Treatment treats up to 16 gallons of gas or diesel fuel.

When greater cleaning is needed, add more Sea Foam – the more you add to fuel, the better it cleans.

Don’t worry if you exceed these amounts: Sea Foam only contains petroleum-based cleaning and lubricating ingredients that CAN’T HARM your engine or fuel system components."




Note last paragraph. Capital letters are theirs, not mine.

If you BROKE a valve, the motor wouldn't run. What happened is you BURNT a valve. More precisely, you burnt an exhaust valve. Two things normally cause burnt exhaust valves; way too lean a mixture usually caused by a bad injector, or insufficient valve lash (how many miles ago were the valves checked?). Another possibility is a failure in the oxygen sensor/EFI computer loop which could make the whole motor run too lean and the exhaust valve with the least lash would be the first to burn.

As far as riding it ANYWHERE, don't. The motor is a ticking time bomb. At the very least, if NOTHING else is wrong with the motor other than the burnt valve and whatever caused the burnt valve is limited to that cylinder (you don't know that), the internal vibration caused by the cylinder imbalance will damage the crankshaft bearings.

The motor could run for hundreds of miles or ten miles. The question is how lucky are you? I would suggest; not very, as you burnt a valve on one of the most bullet proof motorcycle engines around.

As far as fixing or replacing goes, it's really not cost effective to do anything more than a valve job on the bike. If there is ANY damage to the piston (which usually can be seen with a borescope or flexible camera through the sparkplug hole), then it would be more effective to replace with a good used engine or used bike. A valve job involves only removing the head, so there is minimal mechanical labor compared to an engine swap. The majority of cost is the machine shop work.

K motors are long-lived. That means that the motors show up on the used market, taken from bikes that have been crashed. Installing a used motor may be an attractive alternative to opening up and repairing the motor that's now in the bike.

An R80 twin is a wholly different animal from a four-cylinder K bike (even if it's running on three). Both were built by BMW, but they are significantly different mechanically (e.g., the R80 has an electrical system of older design and much less capacity), and will not feel the same. Most folks find they like one flavor more than the other. If you really like the K, you may not like an R80. OTOH, you may like it just fine.

chrisabraham said:

Probably closer to half a bottle of Seafoam in a 5.1 gallon K1100LT tank if I'm honest with you. I'm told the additive superheats the engine when it's running through. Please forgive me, KBiking Gods. That's why I can't have nice things.

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Click to expand...

You may have experienced some bad luck........I concur that there is minimal chance an additive, especially SeaFoam, had anything to do with it.
Hopefully you will get rolling soon.
OM

The R80 is really a different bike altogether. Like a 912 compared to a 928.

Labor-wise, repairing the engine is probably slightly easier than swapping it but you'd want a specialist for that. Parts-wise, repair is probably way cheaper but of course it depends on the cost of the used engine. Repair means you have the chance to clean up all 16 of the valves and start them off like new, which you wouldn't get with a used motor.

Depends on the cost and condition of the used motor. $100 motor with 12,000 miles on it, great. Motor with 90,000 miles, I'd want to rebuild the head anyway so why not rebuild the motor you don't have to remove.

Also depends on the condition of yours. If it has 170,000 on it and sounds terrible, a fresh motor becomes more attractive.